Day 23: strongly connected graph components

diff --git a/2024/45.pl b/2024/45.pl
new file mode 100755 (executable)
index 0000000..97a4351
--- /dev/null
+++ b/2024/45.pl
@@ -0,0 +1,22 @@
+#!/usr/bin/perl -w
+
+use v5.40;
+
+my %conn;
+while (<>) {
+       my ($x, $y) = /\w+/g;
+       $conn{$x}{$y}++;
+       $conn{$y}{$x}++;
+}
+
+my $count;
+for my $x (keys %conn) {
+       for my $y (keys $conn{$x}->%*) {
+               for my $z (keys $conn{$x}->%*) {
+                       next if $z eq $y;
+                       next if !$conn{$z}{$y};
+                       $count++ if $x =~ /^t/ || $y =~ /^t/ || $z =~ /^t/;
+               }
+       }
+}
+say $count / 6;

diff --git a/2024/46.pl b/2024/46.pl
new file mode 100755 (executable)
index 0000000..7310847
--- /dev/null
+++ b/2024/46.pl
@@ -0,0 +1,27 @@
+#!/usr/bin/perl -w
+
+use v5.40;
+
+my %conn;
+while (<>) {
+       my ($x, $y) = /\w+/g;
+       $conn{$x}{$y}++;
+       $conn{$y}{$x}++;
+}
+
+sub walk {
+       my ($set, @todo) = @_;
+       my @max = @$set;
+       X:
+       while (my $x = shift @todo) {
+               for my $y (@$set) {
+                       next X if !$conn{$x}{$y};
+               }
+               my @nset = walk([ @$set, $x ], @todo);
+               @max = @nset
+                       if @nset > @max;
+       }
+       return @max;
+}
+say join(',', walk([], sort keys %conn));
+